JP5504900B2 - Cam mechanism and electromagnetic clutch - Google Patents

Description

  The present invention relates to a cam mechanism and an electromagnetic clutch provided with the cam mechanism.

  Conventionally, a cam member having a cam surface is attracted by the magnetic force of an electromagnetic coil, the cam mechanism is operated by friction at a contact portion with other members generated by the attraction, and the cam member is made stronger by the cam force of the cam mechanism. 2. Description of the Related Art There is known an electromagnetic clutch that controls torque transmission between rotating members by a frictional force caused by pressing against another member. (For example, refer to Patent Document 1).

  The electromagnetic clutch described in Patent Document 1 is applied to a drive system on the rear wheel side of a four-wheel drive vehicle configured to drive front wheels with an engine and drive rear wheels with an electric motor, and stop the electric motor. Sometimes it is arranged between the output shaft and the gears constituting the reduction gear train in order to cut off the connection between the differential device of the rear wheel and the electric motor to reduce the running resistance.

  The electromagnetic clutch includes an electromagnetic coil, a cam member that is attracted to the electromagnetic coil side by the magnetic force of the electromagnetic coil and frictionally contacts a disk-shaped member that rotates integrally with the output shaft, and a cam follower that is interposed between the cam member and the gear. And. A cam surface is formed on each of the facing surfaces of the cam member and the gear, and the cam member and the gear constitute a cam mechanism together with the cam follower.

  This cam member has a disc shape in which an insertion hole for inserting an output is formed at the center, and the friction member that frictionally engages the disc-like member on the surface opposite to the surface on which the cam surface is formed. A surface is formed. The friction surface is formed on the outer peripheral side of the cam surface.

  When the electromagnetic coil is energized during traveling of the vehicle, the cam member is attracted to the disk-shaped member and brought into frictional contact, and is rotated relative to the gear by the frictional force. This relative rotation causes the cam follower to roll on the cam surface, and the cam force of the cam mechanism pushes the cam member more strongly against the disk-shaped member and frictionally engages, so that the torque of the electric motor is transmitted to the differential side. Become.

  On the other hand, when the electric motor is stopped while the electromagnetic coil is not energized, the cam mechanism is neutralized (non-actuated) by the force of the return spring, and the frictional engagement of the cam member is released. As a result, the connection between the electric motor and the differential device is cut off.

JP 2004-17807 A

  The cam member of the electromagnetic clutch configured as described above receives an axial cam force on the cam surface formed on the inner peripheral side with respect to the friction surface, and the friction surface frictionally engages the friction counterpart member. Therefore, the cam member is elastically deformed by the cam force so that the outer peripheral side is separated from the friction counterpart member with the inner peripheral side of the friction surface as a fulcrum. For this reason, the pressing force for frictionally engaging the cam member mainly acts on the inner peripheral side end of the friction surface, and in the extreme case, the outer peripheral side floats from the friction counterpart member. As is well known, the torque T is indicated by the product (T = F × r) of the force F applied to the object and the distance r to the point where the force is applied as seen from the axis of rotation. The part on which the cam force is applied is more effective on the outer peripheral side than on the inner peripheral side.

  However, in the cam member of the electromagnetic clutch configured as described above, the cam force mainly acts on the inner peripheral side end of the friction surface. Therefore, in order to prevent the friction surface from slipping during torque transmission, It is necessary to increase the diameter or to make the angle of the cam surface shallow with respect to the circumferential direction of the cam member. Increasing the diameter of the cam member limits the size and weight of the device, and reducing the cam surface angle increases the relative rotation angle from the neutral position of the cam mechanism until the cam force is generated on the cam member. Decreases.

  Accordingly, an object of the present invention is to provide a cam mechanism capable of suppressing deformation of a cam member due to a cam force, and an electromagnetic clutch provided with the cam mechanism.

In order to achieve the above object, a cam mechanism of the present invention includes a first cam member having a plurality of first cam surfaces formed so as to extend in the circumferential direction, and a relative rotation between the first cam member and an axial direction. A main body formed with a plurality of second cam surfaces for generating cam force, and formed integrally with the main body so as to extend in the radial direction over the inner peripheral side and the outer peripheral side of the plurality of second cam surfaces. And a second cam member having a reinforcing portion that suppresses deformation of the main body due to the cam force, and the reinforcing portion corresponds to each position between the second cam surfaces adjacent in the circumferential direction. Is formed .

According to this configuration, the reinforcing portion receives the cam force on the inner peripheral side and the outer peripheral side of the second cam surface and transmits them in the radial direction of the main body portion. Moreover, according to this structure, the reinforcement part transmits the cam force which generate | occur | produces on several 2nd cam surfaces from the position between each 2nd cam surfaces to radial direction.

  The second cam member has a friction surface that frictionally engages with a friction counterpart member by the cam force on a side surface opposite to the axial direction of the side surface on which the cam surface is formed, and the reinforcing portion includes at least It is good to comprise so that a part may be formed in the range of the radial direction corresponding to the said friction surface.

  According to this configuration, the reinforcing portion transmits the cam force from the second cam surface to the friction surface.

  In order to achieve the above object, an electromagnetic clutch according to the present invention includes a first cam member having a first cam surface formed so as to extend in the circumferential direction, and axial rotation by relative rotation between the first cam member and the first cam member. A second cam member having a second cam surface that generates a cam force, and a main body portion formed with a friction surface that frictionally engages a friction counterpart member by the cam force; and the friction surface of the second cam member is An electromagnetic coil that generates a magnetic force to move the second cam member in the axial direction so as to contact the friction counterpart member, and the second cam member is provided on an inner peripheral side and an outer peripheral side of the second cam surface. And a reinforcing portion that is integrally formed with the main body portion so as to extend in the radial direction and suppresses deformation of the main body portion due to the cam force.

  According to this configuration, the first cam member and the second cam member are relatively rotated by the frictional force generated on the friction surface of the second cam member by energization of the electromagnetic coil, and the cam force generated by the relative rotation is applied to the reinforcing portion. Is received on the inner peripheral side and the outer peripheral side of the second cam surface and transmitted in the radial direction of the main body portion to increase the frictional force on the friction surface.

  According to the present invention, the deformation of the cam member due to the cam force can be suppressed.

FIG. 1 is a schematic diagram showing a configuration of a driving force transmission system of a four-wheel drive vehicle according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view showing a configuration of a driving force transmission device to which the cam mechanism and the electromagnetic clutch according to the first embodiment of the present invention are applied. FIG. 3 is an explanatory view showing a second cam member of the cam mechanism according to the first embodiment of the present invention. FIG. 4 is an explanatory view showing a deformed state of the second cam member of the cam mechanism according to the first embodiment of the present invention together with a comparative example. FIG. 5 is a schematic diagram showing a configuration of an electromagnetic clutch according to a second embodiment of the present invention. FIG. 6 is an explanatory view showing a cam member of a cam mechanism according to a second embodiment of the present invention. FIG. 7 is a schematic view showing a cam member of a cam mechanism according to a third embodiment of the present invention.

[First Embodiment]
FIG. 1 shows a schematic configuration of a driving force transmission system of a four-wheel drive vehicle to which an electromagnetic clutch according to a first embodiment of the present invention is applied. As shown in FIG. 1, a four-wheel drive vehicle 101 includes an engine 102 as a drive source, a transaxle 103 that distributes the output of the engine 102 to a pair of front axle shafts 104 and a propeller shaft 106, and a pair of front axle shafts 104. A driving force transmission device 1 for transmitting the torque of a pair of front wheels 105 and a propeller shaft 106 connected to each to a drive pinion shaft 108, and a rear differential 109 for distributing the torque transmitted to the drive pinion shaft 108 to a pair of rear axle shafts 110. , And a pair of rear wheels 111 connected to each of the pair of rear axle shafts 110.

  The driving force transmission device 1 is supported inside a differential carrier 107 fixed to a vehicle body (not shown) of the four-wheel drive vehicle 101, and can control torque transmission between the propeller shaft 106 and the drive pinion shaft 108. It is configured. When the driving force transmission device 1 connects the propeller shaft 106 and the drive pinion shaft 108 so that torque can be transmitted, the four-wheel drive vehicle 101 enters a four-wheel drive state, and when this connection is released, the four-wheel drive vehicle 101 enters a two-wheel drive state. Become.

  The four-wheel drive vehicle 101 is equipped with a controller 112 that controls the driving force transmission device 1. The controller 112 supplies current to the driving force transmission device 1 based on the rotational speeds of the pair of front wheels 105 and the pair of rear wheels 111, the accelerator opening degree, and the like, and controls torque transmission of the driving force transmission device 1.

(Overall configuration of the driving force transmission device 1)
FIG. 2 is a cross-sectional view illustrating a configuration of the driving force transmission device 1. The driving force transmission device 1 includes a housing 2 that can rotate around a rotation axis O with respect to a differential carrier 107 (shown in FIG. 1), and an inner shaft 3 that is coaxial and relatively rotatable with respect to the housing 2. The main clutch 4 disposed between the housing 2 and the inner shaft 3, the electromagnetic coil 5 held non-rotatable with respect to the differential carrier 107, and the electromagnetic coil 5 are energized to press the main clutch 4. And a cam mechanism 6 that generates a cam force. The electromagnetic coil 5 and the cam mechanism 6 constitute an electromagnetic clutch 10.

(Configuration of housing 2)
The housing 2 includes a front housing 21 and a rear housing 22 coupled so as to rotate integrally with the front housing 21, and is supported inside the differential carrier 107 via a bearing (not shown).

  The front housing 21 is made of, for example, an aluminum alloy that is a nonmagnetic material, and includes a housing space 21a that opens to the rear housing 22 side, and a straight spline fitting portion 21b that is formed on the inner surface of the housing space 21a. The shaft 106 (shown in FIG. 1) is connected to rotate integrally. The accommodating space 21a is filled with lubricating oil at a filling rate of about 80%.

  The rear housing 22 is integrally coupled to the outer member 221 made of a magnetic material such as carbon steel (for example, S35C, S10C) screwed to the inner peripheral surface of the opening of the front housing 21 and the inner side of the outer member 221 by welding or the like. An intermediate member 222 made of a non-magnetic material such as stainless steel, and an inner member 223 made of a magnetic material such as carbon steel integrally joined to the inside of the intermediate member 222 by welding or the like.

  The rear housing 22 is formed with an annular housing space 22 a that opens in the same direction as the opening direction of the housing space 21 a of the front housing 21. Further, a friction surface 22b that frictionally engages a second cam member 62 described later is formed on the side surface of the rear housing 22 opposite to the accommodation space 22a.

(Configuration of inner shaft 3)
The inner shaft 3 is supported inside the housing 2 by a ball bearing 210 interposed between the front housing 21 and a needle bearing 220 interposed between the rear housing 22.

  The inner shaft 3 is formed with a first hollow portion 3b extending in the axial direction from the end surface 3a on the rear housing 22 side, and a straight spline fitting portion 3c is provided on the inner surface of the first hollow portion 3b. The first hollow portion 3b is inserted with the tip of a drive pinion shaft 108 (shown in FIG. 1), and a straight spline fitting portion (not shown) formed at the tip of the drive pinion shaft 108 is the first. It fits into the straight spline fitting part 3c of the hollow part 3b.

  Further, the inner shaft 3 is formed with a second hollow portion 3e extending in the axial direction from the end surface 3d on the front housing 21 side, and lubricating oil is accommodated in the second hollow portion 3e. The first hollow portion 3b and the second hollow portion 3e are separated by a wall portion 3f.

  Further, on the outer surface of the inner shaft 3, a straight spline fitting portion 3g is formed at a portion facing the straight spline fitting portion 21b of the front housing 21.

(Configuration of main clutch 4)
The main clutch 4 has a plurality of outer clutch plates 41 and a plurality of inner clutch plates 42 arranged alternately with the outer clutch plates 41, and both the clutch plates slide in an accommodation space 21a filled with lubricating oil. It is configured as a wet multi-plate clutch.

  The outer clutch plate 41 has a spline fitting portion 41 a on the outer periphery thereof, and the spline fitting portion 41 a is fitted to the straight spline fitting portion 21 b of the front housing 21. As a result, the outer clutch plate 41 is axially movable with respect to the housing 2 and is connected to rotate integrally with the housing 2.

  The inner clutch plate 42 has a spline fitting portion 42 a on its inner peripheral portion, and the spline fitting portion 42 a is fitted to the straight spline fitting portion 3 g of the inner shaft 3. Thereby, the inner clutch plate 42 is axially movable with respect to the inner shaft 3 and is connected so as to rotate integrally with the inner shaft 3. Further, the inner clutch plate 42 has holes 42b through which lubricating oil is circulated at a plurality of locations in the circumferential direction.

(Configuration of electromagnetic coil 5)
The electromagnetic coil 5 is held by a yoke 51 made of a magnetic material such as carbon steel fixed to a differential carrier 107 (shown in FIG. 1), and is disposed in a housing space 22 a of the rear housing 22. The yoke 51 is provided between the inner member 223 with an air gap 51a interposed between the yoke 51 and the inner peripheral surface of the outer member 221 of the rear housing 22 and an air gap 51b between the inner member 223 and the inner member 223. The rear housing 22 is supported via a seal bearing 52.

  The yoke 51 is formed with an annular storage space 51c that opens toward the bottom in the axial direction of the storage space 22a, and the electromagnetic coil 5 is held in the storage space 51c. A current supplied from an electric wire 5 a inserted through a hole 51 d formed in the yoke 51 is energized in the winding of the electromagnetic coil 5.

(Configuration of cam mechanism 6)
The cam mechanism 6 is disposed between the main clutch 4 and the rear housing 22, and has a spherical shape interposed between the first cam member 61, the second cam member 62, and the first cam member 61 and the second cam member 62. The cam follower 63 is configured. The first cam member 61 is disposed closer to the main clutch 4 than the cam follower 63, and the second cam member 62 is disposed closer to the rear housing 22 than the cam follower 63.

(Configuration of the first cam member 61)
The first cam member 61 is an annular member made of a metal material such as carbon steel, and is externally fitted to the inner shaft 3. The first cam member 61 is integrally formed with a pressing portion 611 provided on the main clutch 4 side and a cam portion 612 provided on the cam follower 63 side. The pressing portion 611 is formed with a pressing surface 611 a that faces the inner clutch plate 42 that is located closest to the cam mechanism 6 among the plurality of inner clutch plates 42 of the main clutch 4. The cam portion 612 is formed with a plurality of first cam surfaces 612a on which the cam follower 63 rolls.

  A straight spline fitting portion 611 b is formed on the inner peripheral side of the pressing portion 611 of the first cam member 61, and this straight spline fitting portion 611 b is fitted to the straight spline fitting portion 3 g of the inner shaft 3. . Accordingly, the first cam member 61 is not rotatable relative to the inner shaft 3 and is movable in the axial direction. Further, the first cam member 61 is a second cam member by a disc spring 64 disposed between a step portion 3 h formed on the rear housing 22 side of the straight spline fitting portion 3 g of the inner shaft 3 and the cam portion 622. It is urged in the direction toward 62.

(Configuration of the second cam member 62)
The second cam member 62 is an annular member made of a magnetic material such as carbon steel formed by press working, for example, and an insertion hole 62c through which the inner shaft 3 is inserted is formed at the center thereof. And is fitted so as to be movable in the axial direction. The second cam member 62 includes a body portion 620 and a reinforcing portion 623 that are integrally formed.

  The main body 620 includes a friction part 621 formed with a friction surface 621a that frictionally engages the friction surface 22b of the rear housing 22, and a cam part 622 formed with a second cam surface 622a on which the cam follower 63 rolls. Has been. The friction part 621 is formed on the outer peripheral side of the cam part 622.

  The reinforcing portion 623 is formed on the side surface 62 a opposite to the friction surface 621 a of the main body portion 620 across the friction portion 621 and the cam portion 622. The configuration of the reinforcing portion 623 will be described later.

  The second cam member 62 moves in the axial direction so as to be attracted to the rear housing 22 by the magnetic force generated when the electromagnetic coil 5 is energized, and the friction surface 621a of the friction portion 621 is frictionally engaged with the friction surface 22b of the rear housing 22. Configured to match. Further, the second cam member 62 is biased in a direction toward the first cam member 61 by a disc spring 65. The disc spring 65 is restricted from moving in the axial direction by a snap ring 66 fitted to the outer peripheral surface of the inner shaft 3.

(Configuration of cam follower 63)
The cam follower 63 is made of a metal material such as carbon steel, and is sandwiched between the first cam surface 612a of the first cam member 61 and the second cam surface 622a of the second cam member 62, and the first cam surface 612a and the first cam surface 612a. 2 Rolls on the cam surface 622a. The first cam member 61 and the second cam member 62 are capable of relative rotation within a range in which the cam follower 63 rolls on the first cam surface 612a and the second cam surface 622a.

  The first cam surface 612a and the second cam surface 622a are formed so as to extend in the circumferential direction, and are formed so that the depth in the axial direction at the center is the deepest and becomes shallower toward the end in the circumferential direction. . Accordingly, when the second cam member 62 rotates relative to the first cam member 61 and the cam follower 63 rolls from the position (neutral position) of the first cam surface 612a and the second cam surface 622a in the circumferential direction. The second cam member generates a cam force that is separated from the first cam member 61 in the axial direction.

  The first cam surface 612a and the second cam surface 622a are formed at a plurality of locations in the circumferential direction of the first cam member 61 and the second cam member 62, and the cam follower 63 is disposed at each of the locations.

(Configuration of the reinforcing portion 623 of the second cam member 62)
FIG. 3 shows the shape of the second cam member 62 as viewed from the side surface 62a. In this figure, the inner circumferential circle 621b of the friction surface 621a that frictionally engages the friction surface 22b (shown in FIG. 2) of the rear housing 22 is indicated by a broken line.

  Six second cam surfaces 622 a are arranged at equal intervals on the cam portion 622 of the second cam member 62. Each second cam surface 622 a is formed in an arc shape that curves along the circumferential direction of the second cam member 62. Between the two second cam surfaces 622a adjacent to each other in the circumferential direction, a non-formation region 622b (only one location is indicated by a two-dot chain line in FIG. 3) where no cam surface is formed is provided.

  The side surface 62a is provided with the same number (six) of reinforcing portions 623 as the second cam surface 622a extending from the inner peripheral side toward the outer peripheral side. The reinforcing portion 623 is provided integrally with the second cam member 62 by forming the second cam member 62 to be thicker in the axial direction than the region 62b where the reinforcing portion 623 is not provided.

  The axial thickness of the second cam member 62 where the reinforcing portion 623 is provided is preferably 1.2 to 2.0 times the axial thickness of the region 62b where the reinforcing portion 623 is not provided. . If it is 1.2 times or less, the effect of suppressing the deformation of the second cam member 62 is not sufficient, and if it is 2.0 times or more, interference with the first cam member 61 occurs, and the mass of the second cam member 62 increases. This is because the moving speed in the axial direction due to the magnetic force of the electromagnetic coil 5 decreases.

  The reinforcing portion 623 is provided in a region including the non-formation region 622b, and an end portion 623a on the inner peripheral side of the reinforcing portion 623 is located on the inner peripheral side with respect to the center position 622c in the radial direction of the second cam surface 622a. Yes. Moreover, the outer peripheral end 623b of the reinforcing portion 623 is located on the outer peripheral side of the inner peripheral circle 621b of the friction surface 621a. Thus, the reinforcement part 623 is formed so that it may extend in radial direction over the inner peripheral side and outer peripheral side of the 2nd cam surface 622a.

(Operation of the driving force transmission device 1)
Next, the operation of the driving force transmission device 1 will be described. When the engine 102 of the four-wheel drive vehicle 101 is not started, the cam mechanism 6 is in an inoperative state, and the first cam member 61 and the second cam member 62 are driven by the urging force of the disc spring 64 and the disc spring 65. They are close to each other.

  When the engine 102 starts and the four-wheel drive vehicle 101 starts, the controller 112 supplies a current to the electromagnetic coil 5 of the driving force transmission device 1 so as to set the four-wheel drive state in which the front wheels and the rear wheels are driven. Energize. This energization generates a magnetic flux M in a magnetic path formed by the yoke 51, the outer member 221 of the rear housing 22, the second cam member 62, and the inner member 223 of the rear housing 22, as indicated by a dotted line in FIG. Due to this magnetic force, the second cam member 62 moves in the axial direction toward the rear housing 22, and the friction surface 621 a of the second cam member 62 and the friction surface 22 b of the rear housing 22 come into frictional contact.

  When the housing 2 and the inner shaft 3 are differentially rotated in this state, the cam follower 63 rolls on the first cam surface 612a and the second cam surface 622a, and the first cam member 61 and the second cam member 62 are moved in the axial direction. A cam force for separating is generated. By this cam force, the second cam member 62 is pressed against the rear housing 22 and frictionally engaged, and the first cam member 61 presses the main clutch 4. When the first cam member 61 presses the main clutch 4, the outer clutch plate 41 and the inner clutch plate 42 are frictionally engaged to transmit torque, and the torque of the engine 102 transmitted via the propeller shaft 106 is obtained. Is transmitted to the drive pinion shaft 108 to be in a four-wheel drive state.

  Further, for example, when the four-wheel drive vehicle 101 is in a steady running state in which the four-wheel drive vehicle 101 goes straight at a constant vehicle speed, the controller 112 supplies the electromagnetic coil 5 to a two-wheel drive state in which only the pair of front wheels 105 are driven to improve fuel efficiency. Shut off the power of the.

  When the energization of the electromagnetic coil 5 is interrupted, the second cam member 62 is separated from the rear housing 22 by the biasing force of the disc spring 65. Then, there is no force to relatively rotate the first cam member 61 and the second cam member 62, the cam follower 63 rolls to the neutral position, and the cam mechanism 6 becomes inoperative. Then, the second cam member 62 is returned to a position where the main clutch 4 is not pressed by the biasing force of the disc spring 64. As a result, the frictional engagement between the outer clutch plate 41 and the inner clutch plate 42 is released, and a two-wheel drive state is established.

  Further, when the controller 112 resumes energization to the electromagnetic coil 5 due to, for example, a slip occurring in one of the pair of front wheels 105 of the four-wheel drive vehicle 101, the second cam member 62 is attracted to the rear housing 22. Then, the cam mechanism 6 operates, the main clutch 4 is in a state where torque can be transmitted, and the four-wheel drive vehicle 101 enters the four-wheel drive state.

(Operation of the first embodiment)
4A and 4B show changes in the shape of the second cam member when the cam mechanism is operated and when the cam mechanism is not operated. FIG. 4A shows the second cam member 62 and its peripheral portion according to the present embodiment. These show the 2nd cam member 200 which does not have a reinforcement part as a comparative example, and its peripheral part. The second cam member 200 is configured in the same manner as the second cam member 62 except that the second cam member 200 does not have a reinforcing portion, and includes a friction portion 201 having a friction surface 201a and a cam surface 202a on which the cam follower 63 rolls. The part 202 is integrally formed. In FIG. 4, the outline of the cross-sectional shape when the cam mechanism of the second cam member 62 and the second cam member 200 is not operated is indicated by a two-dot chain line, and the outline of the cross-sectional shape when the cam mechanism is operated is indicated by a solid line. In this figure, the deformation amounts of the second cam member 62 and the second cam member 200 are exaggerated for the sake of explanation.

  As shown in FIG. 4B, when the cam surface 202a of the second cam member 200 receives a cam force from the cam follower 63, the second cam member 200 is elastically deformed, and the cam portion 202 is compared with the state before the deformation. Is displaced to the rear housing 22 side, and the frictional portion 201 is displaced to the side opposite to the rear housing 22 side, particularly at the outer periphery thereof. As a result, the cam force is concentrated on the inner peripheral side of the friction surface 201a.

  On the other hand, as shown in FIG. 4A, since the second cam member 62 includes the reinforcing portion 623, the deformation amount when the cam mechanism 6 is operated is suppressed to, for example, less than half of that of the second cam member 200. ing. Therefore, as compared with the second cam member 200, the concentration of the force pressing the second cam member 62 against the rear housing 22 on the inner peripheral side of the friction surface 621a is alleviated, and the cam force is greater than that of the second cam member 200. It acts on the friction surface 621a evenly.

(Effects of the first embodiment)
According to the first embodiment of the present invention described above, the following effects can be obtained.

(1) Since the deformation of the second cam member 62 during operation of the cam mechanism 6 is suppressed by providing the reinforcing portion 623, the cam force is generated on the entire friction surface 621a as compared with the case where the reinforcing portion 623 is not provided. Works equally well. As a result, at the time of differential rotation between the housing 2 and the inner shaft 3, the friction torque generated in the second cam member 62 increases, and the required torque transmission capacity can be obtained even if the driving force transmission device 1 is made compact. It can be secured.

(2) Since the reinforcing portion 623 is formed not in the entire circumferential direction of the side surface 62a of the second cam member 62 but in a part thereof, for example, compared with a case where the entire second cam member is formed thick. The second cam member 62 can be reduced in weight, and the operation response of the cam mechanism 6 can be improved.

(3) As for the 2nd cam member 62, the edge part 623a of the inner peripheral side of the reinforcement part 623 is located in the inner peripheral side rather than the center position 622c of the radial direction of the 2nd cam surface 622a, and the edge part 623b of the outer peripheral side is located. Since the friction surface 621 a is configured to be positioned on the outer peripheral side of the inner peripheral circle 621 b, the cam force can be transmitted from the cam portion 622 to the friction portion 621 via the reinforcing portion 623.

(4) Since the reinforcing portion 623 is provided integrally with the second cam member 62, the reinforcing portion 623 is formed simultaneously with the formation of the cam portion 622 and the friction portion 621 of the second cam member 62, for example, by press molding of the material. can do.

[Second Embodiment]
FIG. 5 is an overall view showing a schematic configuration of the electromagnetic clutch 11 including the cam mechanism 8 according to the second embodiment of the present invention and its peripheral portion. The electromagnetic clutch 11 functions as a brake device for preventing the cylindrical rotating member 80 from rotating with respect to the casing 9 that is a non-rotating member, and is used, for example, to switch a torque transmission path by a planetary gear mechanism. .

  The electromagnetic clutch 11 includes a rotating member 80, a spherical cam follower 83 that rolls on a cam surface 82a formed on the flange 82 of the rotating member 80, and a plate in which a cam surface 841a is formed on a surface facing the cam surface 82a. And a yoke 72 made of a magnetic material that holds the electromagnetic coil 71. The electromagnetic coil 71 generates a magnetic force that moves the cam member 84 in the axial direction. The rotating member 80 is an example of the first cam member of the present invention, and the cam member 84 is an example of the second cam member of the present invention.

(Configuration of Rotating Member 80)
The rotating member 80 includes a cylindrical portion 81 in which a through-hole through which a shaft (not shown) is inserted is formed on the inner surface, and an annular flange portion that protrudes radially outward from one axial end of the cylindrical portion 81. 82 is integrally formed. A straight spline fitting portion 81 a formed along the rotation axis O ₂ for restricting relative rotation between the shaft and the rotation member 80 is provided on one side in the axial direction of the inner peripheral surface of the cylindrical portion 81. Yes. An inner ring 751 of a ball bearing 75 is fitted to the outer peripheral surface of the cylindrical portion 81 that is outside the straight spline fitting portion 81a.

  A cam surface 82a formed on one side surface of the flange portion 82 in the axial direction (the side on which the straight spline fitting portion 81a is formed) extends in the circumferential direction of the rotating member 80 and has an axial depth at the central portion thereof. Is deepest and becomes shallower toward the end in the circumferential direction.

(Configuration of cam member 84)
The cam member 84 is an annular member made of a metal material such as carbon steel in which an insertion hole 84 a through which the rotation member 80 is inserted is formed at the center, and is externally fitted to the cylindrical portion 81 of the rotation member 80. The cam member 84 has a body portion 840 including a cam portion 841 formed with a cam surface 841 a and a friction portion 842 provided on the outer peripheral side of the cam portion 841, and a side surface facing the flange portion 82 of the body portion 840. The formed reinforcing portion 843 is integrally formed. Details of the reinforcing portion 843 will be described later.

  The cam surface 841a of the cam portion 841 extends in the circumferential direction of the cam member 84, and is formed so that the axial depth at the center portion is the deepest and becomes shallower toward the end portion in the circumferential direction.

  An inner peripheral side that frictionally engages an inner peripheral friction surface 72a and an outer peripheral friction surface 72b of a yoke 72, which will be described later, on a side surface on the one axial side of the friction portion 842 (a side surface opposite to the reinforcing portion 843). A friction surface 842a and an outer peripheral friction surface 842b are formed.

  Further, the cam member 84 is urged toward the flange portion 82 by the disc spring 73. The disc spring 73 is restricted from moving in the axial direction by a spacer 74 disposed between the disc bearing 73 and the inner ring 751 of the ball bearing 75.

  Cam surfaces 82 a are formed at a plurality of locations in the circumferential direction on the flange portion 82 of the rotating member 80, and the same number of cam surfaces 841 a are formed on the cam portions 841 of the cam member 84. The cam follower 83 is interposed between each cam surface 82a and the corresponding cam surface 841a. The cam member 84 can rotate relative to the rotating member 80 in a range where the cam follower 83 rolls on the cam surface 841a and the cam surface 82a of the rotating member 80.

(Configuration of yoke 72)
The yoke 72 is made of a magnetic material such as carbon steel, is disposed so as to face the cam member 84 in the axial direction, and is fixed to the casing 9 by a bolt 91 so as not to be relatively rotatable and axially movable. The yoke 72 is formed with an annular recess 720 having a U-shaped cross section that is open toward the cam member 84 in the axial direction, and the electromagnetic coil 71 is held in the annular recess 720. An annular inner peripheral friction surface 72a is formed on the inner surface of the annular recess 720 facing the cam member 84, and an annular outer friction surface 72b is formed on the outer surface of the annular recess 720 facing the cam member 84. Is formed.

  An outer ring 752 of a ball bearing 75 is fitted to the inner peripheral surface of the yoke 72, and the yoke 72 supports the rotating member 80 in a rotatable manner. The ball bearing 75 is provided on the inner peripheral surface of the yoke 72, with the axial position of the inner ring 751 fixed by a step portion 81 b provided on the outer peripheral surface of the cylindrical portion 81 of the rotating member 80 and the snap ring 753. The position of the outer ring 752 in the axial direction is fixed by the stepped portion 72c and the snap ring 754.

  The electromagnetic coil 71 is held in the annular recess 720 of the yoke 72 and is prevented from coming off by a snap ring 721. A current is supplied to the electromagnetic coil 71 by an unillustrated electric wire.

(Configuration of reinforcing portion 843)
FIG. 6 shows a side surface of the cam member 84 on the side where the reinforcing portion 843 is provided. In this figure, the inner circumference circle 842c and the outer circumference circle 842d of the inner circumference side friction surface 842a and the inner circumference circle 842e of the outer circumference side friction surface 842b are indicated by broken lines.

  Six cam surfaces 841a are arranged at equal intervals on the cam portion 841 of the cam member 84. Each cam surface 841 a is formed in an arc shape that curves along the circumferential direction of the cam member 84. Between the two cam surfaces 841a adjacent to each other in the circumferential direction, a non-formation region 841b (only one location is indicated by a two-dot chain line in FIG. 6) where no cam surface is formed is provided.

  The cam member 84 is provided with the same number (six) of reinforcing portions 843 as the cam surface 841a extending from the inner peripheral side toward the outer peripheral side. The reinforcing portion 843 is provided integrally with the cam member 84 by forming the cam member 84 thicker in the axial direction than the region 84b where the reinforcing portion 843 is not provided.

  The reinforcing portion 843 is provided in a region including the non-forming region 841b, and an end portion 843a on the inner peripheral side of the reinforcing portion 843 is located on the inner peripheral side with respect to the center position 841c in the radial direction of the cam surface 841a. It reaches the inner peripheral surface of 84a. Further, the outer end 843b of the reinforcing portion 843 is located on the outer peripheral side with respect to the inner peripheral circle 842e of the outer peripheral friction surface 842b. Thus, the reinforcement part 843 is formed in the range which hits the axial direction opposite side of the inner peripheral side friction surface 842a and the outer peripheral side friction surface 842b.

(Operation of electromagnetic clutch 11)
When energizing of solenoid coil 71, as indicated by a broken line in FIG. 5, the magnetic flux M ₂ is generated in the magnetic path formed by the yoke 72 and the cam member 84, the cam member 84 are attracted to the side of the yoke 72, The inner peripheral friction surface 842a of the cam member 84 is in frictional contact with the inner peripheral friction surface 72a of the yoke 72, and the outer peripheral friction surface 842b of the cam member 84 is in frictional contact with the outer peripheral friction surface 72b of the yoke 72.

  When the rotating member 80 rotates in this state, the cam follower 83 rolls on the cam surface 82a and the cam surface 841a, and a cam force that separates the cam member 84 in the axial direction from the flange portion 82 of the rotating member 80 is generated. With this cam force, the cam member 84 is pressed toward the yoke 72, and the frictional forces of the inner peripheral friction surface 842a and the inner peripheral friction surface 72a, and the outer peripheral friction surface 842b and the outer peripheral friction surface 72b increase. The cam member 84 and the yoke 72 are frictionally engaged. Thereby, the rotation member 80 is prevented from rotating with respect to the casing 9.

  On the other hand, when the energization of the electromagnetic coil 71 is interrupted, the cam member 84 is separated from the yoke 72 by the biasing force of the disc spring 73, and the frictional engagement between the cam member 84 and the yoke 72 is released. Then, the cam follower 83 moves to the deepest part (neutral position) of the cam surface 841a and the cam surface 82a, and the cam force disappears. As a result, the rotating member 80 can rotate together with the cam follower 83, the cam member 84, and the disc spring 73.

(Effect of the second embodiment)
According to the second embodiment of the present invention described above, since the cam member 84 is directly frictionally engaged with the yoke 72 in addition to the same effect as the first embodiment, the electromagnetic force can be reduced with a small number of parts. The clutch 11 can be configured.

[Third Embodiment]
FIG. 7 shows a cam member 84A of the electromagnetic clutch 11 according to the third embodiment of the present invention. The electromagnetic clutch 11 according to the present embodiment has the same configuration as that of the second embodiment except that the cam member 84 is replaced with the cam member 84A. The cam member 84A is different in the structure of the reinforcing portion 85 from the reinforcing portion 843 of the cam member 84, but is otherwise the same. Therefore, the same components are denoted by the same reference numerals and description thereof is omitted.

  The reinforcing portion 85 provided on the cam member 84A extends from the annular reinforcing portion 851 formed in an annular shape along the circumferential direction of the cam member 84A and the outer end 851a of the annular reinforcing portion 851 to the outer peripheral side. And a spoke-shaped reinforcing portion 852 formed. The reinforcing portion 85 is provided integrally with the cam member 84A by forming the cam member 84A thicker in the axial direction than the region 85b where the reinforcing portion 85 is not provided.

  The annular reinforcing portion 851 is formed in a region including the cam surface 841a, and a part of the annular reinforcing portion 851 is formed in a range corresponding to the axially opposite side of the inner peripheral friction surface 842a.

  The spoke-like reinforcing portion 852 is formed radially from the outer peripheral end 851a of the annular reinforcing portion 851, and the outer peripheral end 852a is located on the outer peripheral side of the inner peripheral circle 842e of the outer peripheral friction surface 842b. Yes. Further, the same number (six) of the spoke-shaped reinforcing portions 852 as the cam surfaces 841a are provided on the outer peripheral side corresponding to the position between the adjacent cam surfaces 841a.

  According to the present embodiment, there are the same effects as the effects of the second embodiment. Further, since the cam force received by the cam surface 841a from the cam follower 83 is dispersed in the circumferential direction by the annular reinforcing portion 851, the cam force is concentrated around the inner peripheral friction surface 842a, which is the back side of the position where the cam follower 83 exists. The cam force is more accurately transmitted to the spoke-like reinforcing portion 852 via the annular reinforcing portion 851. Therefore, the deformation of the cam member 84A is more reliably suppressed.

[Other embodiments]
As mentioned above, although the cam mechanism and electromagnetic clutch of the present invention have been described based on the above-described embodiment, the present invention is not limited to the above-described embodiment, and can be variously modified without departing from the scope of the present invention. For example, the following modifications are possible.

(1) The reinforcing portions in the first and second embodiments and the spoke-like reinforcing portions in the third embodiment are provided with a constant width along the radial direction, but with respect to the radial direction. You may provide inclining. In addition, the width dimension of the reinforcing part or the spoke-like reinforcing part may not be constant, for example, it is formed so that the width in the circumferential direction becomes wider toward the inner peripheral side or outer peripheral side of the cam surface, or toward the inner peripheral side and the outer peripheral side. May be. Further, the thickness of the reinforcing portion is not limited to a constant value.

(2) In each of the above embodiments, the cam member is frictionally engaged with the rear housing or the yoke when the electromagnetic coil is energized, and the frictional engagement is released by the biasing force of the disc spring when deenergized. On the contrary, the cam member is frictionally engaged with other members by the biasing force of an elastic member such as a disc spring when the electromagnetic coil is not energized, and the frictional engagement is released by the magnetic force when the electromagnetic coil is energized. You may comprise.

(3) There are no particular restrictions on the use and application object of the cam mechanism and electromagnetic clutch.

DESCRIPTION OF SYMBOLS 1 ... Driving force transmission device, 2 ... Housing, 3 ... Inner shaft, 3a ... End surface, 3b ... Hollow part, 3c ... Straight spline fitting part, 3d ... End surface, 3e ... Hollow part, 3f ... Wall part, 3g ... Straight Spline fitting portion, 3h ... step portion, 4 ... main clutch, 5 ... electromagnetic coil, 5a ... electric wire, 6 ... cam mechanism, 8 ... cam mechanism, 9 ... casing, 9a ... recess, 10,11 ... electromagnetic clutch, 21 ... Front housing, 21a ... Housing space, 21b ... Straight spline fitting part, 22 ... Rear housing, 22a ... Housing space, 22b ... Friction surface, 41 ... Outer clutch plate, 41a ... Spline fitting part, 42 ... Inner clutch plate 42a ... spline fitting part, 42b ... hole, 51 ... yoke, 51a, 51b ... air gap, 51c ... accommodation space, 51d ... hole, 2 ... Seal bearing, 61 ... 1st cam member, 62 ... 2nd cam member, 62a ... Side surface, 62b ... Area | region, 62c ... Insertion hole, 63 ... Cam follower, 64, 65 ... Disc spring, 66 ... Snap ring, 71 ... Electromagnetic coil, 72a ... inner friction surface, 72b ... outer friction surface, 72c ... stepped portion, 73, 76 ... disc spring, 74 ... spacer, 75 ... ball bearing, 80 ... rotating member, 81 ... cylindrical portion, 81a ... straight spline fitting part, 81b ... step part, 82 ... collar part, 82a ... cam surface, 83 ... cam follower, 84, 84A ... cam member, 84a ... insertion hole, 84b ... area, 85 ... reinforcing part, 85b ... area , 91 ... Bolt, 101 ... Four-wheel drive vehicle, 102 ... Engine, 103 ... Transaxle, 104 ... Front axle shaft, 105 ... Front wheel, 106 ... Propeller shaft, 107 Differential carrier 108 ... Drive pinion shaft 109 ... Rear differential 110 ... Rear axle shaft 111 ... Rear wheel 112 ... Controller 200 ... Cam member 201 ... Friction part 201a ... Friction surface 202 ... Cam part 202a ... Cam surface, 210 ... ball bearing, 220 ... needle bearing, 221 ... outer member, 222 ... intermediate member, 223 ... inner member, 611 ... pressing portion, 611a ... pressing surface, 611b ... straight spline fitting portion, 612 ... cam portion , 612a ... first cam surface, 620 ... main body portion, 621 ... friction portion, 621a ... friction surface, 621b ... inner circle, 622 ... cam portion, 622a ... second cam surface, 622b ... non-forming region, 622c ... center Position, 623 ... reinforcing part, 623a, 623b ... end, 720 ... annular recess, 721 , 753,754 ... Snap ring, 751 ... Inner ring, 752 ... Outer ring, 840 ... Main body part, 841 ... Cam part, 841a ... Cam surface, 841b ... Non-formation region, 841c ... Center position, 842 ... Friction part 842a ... Inner circumference Side friction surface, 842b ... outer peripheral side friction surface, 842c, 842e ... inner circumference circle, 842d ... outer circumference circle, 843 ... reinforcement part, 843a, 843b ... end part, 851 ... annular reinforcement part, 851a, 852a ... end part, 852 ... Spoke-shaped reinforcing part, M, M ₂ ... Magnetic flux, O, O ₂ ... Rotary shaft

Claims (3)

A first cam member having a plurality of first cam surfaces formed to extend in the circumferential direction;
A main body portion on which a plurality of second cam surfaces that generate axial cam force by relative rotation with the first cam member are formed, and an inner peripheral side and an outer peripheral side of the plurality of second cam surfaces. A second cam member formed integrally with the main body portion so as to extend in the radial direction and having a reinforcing portion that suppresses deformation of the main body portion due to the cam force ;
The said reinforcement part is a cam mechanism currently formed corresponding to each position between the said 2nd cam surfaces adjacent to the circumferential direction . The second cam member has a friction surface that frictionally engages with a friction counterpart member by the cam force on a side surface opposite to the axial direction of the side surface on which the cam surface is formed,
The cam mechanism according to claim 1, wherein at least a part of the reinforcing portion is formed in a radial range corresponding to the friction surface. A first cam member having a first cam surface formed to extend in the circumferential direction;
A second cam member having a second cam surface that generates an axial cam force by relative rotation with the first cam member, and a main body portion formed with a friction surface that frictionally engages with a friction counterpart member by the cam force. When,
An electromagnetic coil that generates a magnetic force to move the second cam member in the axial direction so that the friction surface of the second cam member is brought into contact with the friction counterpart member,
The second cam member is formed integrally with the main body portion so as to extend in a radial direction across an inner peripheral side and an outer peripheral side of the second cam surface, and suppresses deformation of the main body portion due to the cam force. An electromagnetic clutch having a reinforcing portion.

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